作者:Céu M. Sousa、Jerome Berthet、Stephanie Delbaere、Paulo J. Coelho
DOI:10.1021/jo3003216
日期:2012.4.20
colored photoisomers, one of which fades very slowly and is responsible for a persistent residual color. UV excitation of these new uncolored fused-naphthopyrans leads to the formation of only one colored photoisomer that fades completely to the uncolored state in few seconds/minutes following a monoexponential decay law, thus avoiding the problem of the residual coloration typically observed with naphthopyrans
由4-(溴甲基)苯并香豆素经几个步骤合成了一系列新的光致变色稠合萘并吡喃并具有吡喃环和萘核之间的烷基桥。在这些新的稠合萘并吡喃中,烷基桥的存在阻止了一种长寿命的光异构体的形成,因此对它们的光致变色特性产生了巨大影响:普通萘并吡喃的紫外线辐射会产生两种异构的有色光异构体,其中一种会褪色缓慢并造成持久的残留颜色。这些新的未着色的融合萘并吡喃的紫外线激发导致仅一种有色的光异构体的形成,该异构体遵循单指数衰减定律在几秒/分钟内完全褪色成未着色的状态,从而避免了萘并吡喃中通常观察到的残留着色的问题。